Envirogen has been awarded a $0.9M contract to test a novel biological treatment, using a Fluidized Bed Reactor (FBR), for groundwater contaminated by 1,4-Dioxane (1,4-D) and dilute levels of chlorinated volatile organic compounds (cVOCs).
The contract was awarded by the Environmental Security Technology Certification Program (ESTCP) through the US Army Corp of Engineers.
The R&D-based project will study the use of a butane degrading microbe in an FBR to consume isobutane and cometabolically treat 1,4-D and the cVOCs. The three-year project, commencing Q4 2022, comprises bench-scale testing in New Jersey followed by a pilot-scale off-site demonstration in Tennessee in 2024/5.
“The butanotroph microbe-based treatment approach is novel because it’s the first time it will have been tested to remove these co-contaminants from groundwater in an ex-situ bioreactor,” says Dr. Todd Webster, Vice President, Envirogen Technologies.
“The project’s overall objective is to demonstrate and validate the use, performance and costing of an FBR, using the butane degrading microbe for the treatment of the comingled contaminants.”
DoD remediation plan
The project is part of the Department of Defense (DoD) remediation plan for clean-up of water contaminated by 1,4-D and other recalcitrant chemicals. The DoD has used cVOCs as degreasing agents and cleaning agents for years, with 1,4-D added as a chlorinated solvent stabilizer, resulting in these chemicals co-contaminating ground water at DoD sites. Historically, at such sites, cVOCs are treated by air stripping, followed by carbon or advanced oxidation processes (AOP) such as UV light-hydrogen peroxide or ozone-hydrogen peroxide to treat the 1,4-D.
Dr. Webster states, “Multiple treatment processes of air stripping and AOP are the traditional means to remove these co-contaminants from groundwater. Although these technologies are effective, they can also be expensive because of the necessary capital and electricity requirements.
“Our novel use of a single biological technology to treat both 1,4-D and dilute cVOCs in groundwater would provide improved life-cycle treatment costs for the DoD at numerous contaminated sites.”
Current data suggest that a biological system to treat these co-contaminant streams to required regulatory levels is potentially both feasible and sustainable. Envirogen’s FBR is an efficient fixed-film bioreactor in which a high concentration of naturally occurring biomass containing the butanotroph microbe is attached to a fluidized medium. Biological treatment of the contaminated water occurs within that biomass-medium interface.
Envirogen was awarded the project based on a competitive bid process, focusing on the company’s innovative technologies and expertise in treating emerging contaminants. Envirogen has partnered with APTIM Federal Services, a subcontractor in this project, to collaborate on the bench-scale element work. APTIM specializes in critical infrastructure, technical and data solutions and related services including environmental remediation.
The image below shows a pilot FBR system representative of what Envirogen will be providing for the project: